What are my chances of giving birth vaginally after having a c-section?

As long as you're an appropriate candidate for a vaginal birth after a cesarean, also known as a VBAC, there's a good chance you'll succeed. Of course, your chances of success are higher if the reason for your prior c-section isn't likely to be an issue this time around.

For example, a woman who has already had an easy vaginal delivery and then had a c-section when her next baby was breech is much more likely to have a successful VBAC than one who had a c-section after being fully dilated and pushing for three hours with her first baby who was small and properly positioned. (Having given birth vaginally boosts your odds dramatically.)

That said, it's impossible to predict with any certainty which women will achieve a vaginal delivery and which will end up with a repeat c-section. Overall, about 60 to 80 percent of women who attempt a VBAC deliver vaginally.

If you decide to try it, you'll need a caregiver who supports the idea. Your caregiver must also have admitting privileges at a hospital that allows VBACs and where appropriate coverage is available around-the-clock.

An increasing number of hospitals have strict criteria regarding who will be allowed to attempt a VBAC because of controversy about their safety, specifically the potential for uterine rupture - a rare injury, but one that can be catastrophic for mother and baby.

What would make me a good candidate for a VBAC?

According to the American College of Obstetricians and Gynecologists, you're a good candidate for a vaginal birth after a c-section if you meet all of the following criteria:

You've had only one previous cesarean delivery and it was done with a low transverse (horizontal) incision. Having had more than one c-section or an incision in your upper uterus that was vertical - also known as "classical" - or T-shaped puts you at a greatly increased risk for uterine rupture. Note that the type of scar you have on your belly may not match the one on your uterus, so your practitioner will need to review a copy of your c-section report.

Your pelvis seems large enough to allow your baby to pass through safely. (While there's no way to know this for sure, your practitioner can examine your pelvis and make an educated guess.)

You've never had any other extensive uterine surgery, such as a myomectomy to remove fibroids.

You've never had a uterine rupture.

You have no medical condition or obstetric problem that would make a vaginal delivery risky.

There's a physician on site who can monitor your labor and perform an emergency c-section if necessary.

There's an anesthesiologist, other medical personnel, and equipment available around-the-clock to handle an emergency situation for you or your baby.

VBACs are controversial, and you may find it difficult to decide whether to attempt one. The best approach is to talk to your practitioner about your individual chance of success. Start the discussion early in pregnancy so you'll have time to carefully weigh the benefits and risks.

What are the benefits of having a VBAC?

A successful VBAC allows you to avoid major abdominal surgery and the risks associated with it - including a higher risk of excessive bleeding, which can lead to a blood transfusion or even a hysterectomy in rare cases, as well as a higher risk of developing certain infections. A c-section requires a longer hospital stay than a vaginal birth, and your recovery is generally slower and more uncomfortable.

If you plan to have more children, you should know that every c-section you have increases your risk in future pregnancies of placenta previa and placenta accreta, in which the placenta implants too deeply and doesn't separate properly at delivery. These conditions can result in life-threatening bleeding and hysterectomy. And a recent large study found that the risk of some other delivery complications also rises with each c-section.

Finally, if you were disappointed about having a previous c-section, you may feel a tremendous sense of pride and accomplishment at being able to deliver vaginally this time around.

What are the risks of attempting a VBAC?

Even if you're a good candidate for a VBAC, there's a very small (less than 1 percent) risk that your uterus will rupture at the site of your c-section incision, resulting in severe blood loss for you and possibly oxygen deprivation for your baby.

The risk of uterine rupture is somewhat higher if your labor needs to be induced or augmented. Some experts think it's reasonable to abandon the attempt at a VBAC if it looks like you're going to need oxytocin (Pitocin) to get your contractions going or keep them moving.

Also, if you end up being unable to deliver vaginally, you could endure hours of labor only to have an unplanned c-section. And while a successful VBAC is less risky than a scheduled repeat c-section, an unsuccessful VBAC requiring a c-section after the onset of labor carries more risk than a scheduled c-section.

With an unplanned c-section after laboring, you have a higher chance of surgical complications, such as excessive bleeding that could require a blood transfusion or a hysterectomy in rare cases and infections of the uterus and the incision. And the risk of complications is even higher if you end up needing an emergency cesarean.

Finally, there is the risk of the baby having a serious complication that could lead to long-term neurological damage or even death. While this risk is very small overall, it's higher in women who undergo labor before a c-section.

What kind of interventions will I need if I attempt a VBAC?

If you decide to try for a vaginal birth, you'll need continuous electronic fetal monitoring because a change in your baby's heartbeat is usually the earliest sign that there might be a problem. You'll also need an IV, and you'll have to refrain from eating anything during labor in case you require an emergency c-section later.